SEG3430 Tutorial 1

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SEG3430 Tutorial 1

• System Development Life Cycle (SDLC)

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SYSTEM ANALYSIS DESIGN -- SAD

• Not just about PROGRAMMING
• Analysis Activities Design Activities
• Identification of problems
• Proposed solution
• Design and implementation of the solution

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Methodology

• SDLC System Development Life Cycle
• Others
• OOAD Object-Oriented Analysis Design
• RAD Rapid Application Development

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Wrong System Development approach

• General type of System Development
• Separate planning hardly modified
• System design and analysis work interactively
  during Implementation

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Definition of SDLC

• A conceptual model used in project management
  that describes the stages involved in an
  information system development project, from an
  initial feasibility study through maintenance of
  the completed application.

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Definition of SDLC

• The process of
• (1) understanding how an information system can
  support business needs
• (2) designing the system
• (3) building it and
• (4) delivering to the users

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Different Phases for SDLC

• A systematic approach to problem solving and is
  made up of several phases, each comprised of
  multiple steps
• Preliminary Investigation Why
• Analysis Who, What, Where and When
• Logical Design How
• Physical Design How
• Implementation
• Maintenance

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A Letter of Requirement

• Dear System Analyst
• I am a retailing manager. Due to the large
  demands of our goods, we want to open up a system
  that sells goods automatically to consumers all
  the time. Let us have a meeting to talk about it.
• Regards,
• Retailing Manager

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ANSWER Vending Machine

• Supposed we assign SDLC in the system development
  of vending machine WHAT DOES IT LOOK LIKE?
• Preliminary Investigation
• Analysis
• Logical Design
• Physical Design
• Implementation
• Maintenance

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Preliminary Investigation

• Identifying business value
• Gain an appropriate understanding of the business
  problem domain
• Estimate the investment and reward on the project
• e.g. the percentage of cost reduction paid in
  warehousing
• Analyze feasibility
• Technical, economical and organizational
• Analyzes the information needs of the end users
• e.g. co-ordination among sales, warehouse keeper,
  merchandiser or more parties

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Preliminary Investigation

• Develop work plan
• Decide the sequence of process completion
• Stock checking merchandising system gt login
  system
• PERT Chart
• Staff the project
• Control and direct project
• Prioritize - requirements can be classified as
  mandatory, desirable, or optional.

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Analysis

• Strategy analysis
• As-is system and to-be system
• Iterative cycle of steps until they are
  considered accurate and complete
• e.g. integration of old and future system
• Gathering business requirements
• Interview or Questionnaire
• Use cases analysis
• Describe how an external user triggers an event
  to which the system must respond
• Eg A library patron borrow or return a book

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Analysis

• Process modeling of existing system
• Representing how business operates
• Data flow diagram (DFD)
• e.g. Data flow for the login system
• Data modeling of existing system
• Balance with process models
• Entity-Relationship Diagram (ER diagram)
• e.g. Relationship between attributes for
  warehouse keeper and merchandiser

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Logical Design

• Refine the existing logical models with the
  proposed system functions
• Requirement definition use cases
• Specify requirements without expressing computer
  alternatives and technology details.
• Deliverable System Proposal
• -- Implementation Independent

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Physical Design

• Architecture design
• Specifications for the hardware, software and
  data resources from the definition phase into a
  set of technical design
• Program design
• Programming instructions necessary
• Existing systems must be integrated in the design
• Data storage design
• RDBMS, XML or raw text file
• Deliverable System Specification

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Implementation

• Construction
• Program building
• Creates and programs the final system
• Program and system testing
• Evaluates the system's actual functionality in
  relation to expected or intended functionality
• Done systematically and results documented
  carefully
• Avoid patches delivery after software release

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Implementation

• Installation
• Conversion strategy
• Direct, parallel or pilot conversion
• Training plan
• Helping users accomplish their tasks
• Support plan
• On-demand training , online support or helpdesk

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Maintenance

• Detailed modifications to the new system
• Correct a problem not discovered during final
  testing

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Waterfall SDLC model
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Waterfall SDLC model

• One of the classic approach most development
  approaches derived from it
• Describes a development method that is sequential
  and also iterative

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Waterfall SDLC model

• Advantage
• Allows for departmentalization and managerial
  control
• Allows for reverting back to a previous phase to
  correct or refine
• More than one phase may be parallel conducted
• Disadvantage
• Time consuming for the whole development period
• Maintenance cost

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Relative Cost of Fixing an Error
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Small Tasks

• Choose a system that you are familiar, figure out
  each phase of its development
• E.g. On-line course selection system. In this
  case, issues of data should also be taken into
  consideration.

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Small Tasks

• Comparing the job duties difference
• System Analyst
• Application Programmer
• Independent Analyst
• Find out the common and different responsibility
  among these 3 roles
• Search in JobsDB, SCMP, Jiu Jik , etc.
• Discuss in next tutorial

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Source

• http//en.wikipedia.org/wiki/Systems_Development_L
  ife_Cycle
• http//www.webopedia.com/TERM/S/SDLC.html
• http//searchvb.techtarget.com/sDefinition/0,,sid8
  _gci755068,00.html